Arteries carry oxygenated blood from the heart to the sites in the body where it is used: the organs and tissue. From there, veins transport the deoxygenated blood back to the heart, which then pumps the blood into the lungs where it is again enriched with oxygen.
Medical conditions that may lead to transplantation
Vessels can become narrower and blocked, for instance due to deposits in the vessel walls (arteriosclerosis), blood clot formation (thrombosis), infections or scarring. In some cases, vessel transplantations are performed. They can be used as a bypass or to reconstruct a damaged vessel.